Wood chip conveying system



Jam 7, 1958 w. T. s. MONTGOMERY 2,819,123

woon can CONVEYING SYSTEM F1166. Jan. 27, 1956 1 2 Sheets-Sheet 1 INVENTO'R ATTORNEYS Jan. 7, 1958 w T. s. MONTGQMERY 2,319,123

wooo CHIP CONVEYING SYSTEM Filed Jan. 27. 1956 2 Sheets-Sheet 2 ATTORNEYS United grates Patent WOOD CHIP CONVEYING SYSTEM William T. S. Montgomery, Jacksonville, Fla.

Application January 27, 1956, Serial No. 561,736

7 Claims. (Cl. 302--59) This invention relates to conveyor systems and more particularly relates to a pneumatic system for conveying wood chips or similar materials to a discharge point remote from the source of the chips.

It has heretofore been common practice to handle grain and similar materials through the use of pneumatic conveying systems wherein the grain or other material is carried through a conduit by a high velocity stream of air or other gas. This system has been quite satisfactory for handling such materials where they are to be conveyed to a substantially closed container, such as a boxcar as shown in United States Patent 672,409. When the container is open, however, I have found that this system is completely unsatisfactory due to the fact that the high velocity stream of air not only blows the material into the container but also immediately blasts it right out.

The desirability of reducing the conveying gas velocity prior to discharge has prompted the use of various types of cyclones and other velocity reducing chambers, all of which are bulky, relatively high cost items needing periodic maintenance. In addition to this, such cyclones have usually been installed in vertical conduits so that the reduction in gas velocity has not been completely imparted to the particles being conveyed by reason of the fact that mere slowing of the gas velocity will not theoretically slow a falling particle which continues to accelerate under the acceleration of gravity. While the effect of wind resistance tends to counteract this acceleration so that in practical cases no real acceleration occurs after the velocity reduction, the particle velocity does remain relatively high.

I have now found that the foregoing difficulties may be eliminated and a satisfactory pneumatic conveyor system provided if the velocity of the conveying gas is reduced while the material is moving in a substantially horizontal direction, particularly where the reduction in velocity occurs at such a position that the moving particles retain a momentum which is merely sufficient to bring such particles to a downwardly extending conduit into which they fall by gravity. I have further found that this may be accomplished without the use of cyclones or other similar vessels by the use of a novel conduit arrangement.

It is accordingly a primary object of the present invention to provide a pneumatic conveying system capable of discharging a discrete particle material into an open container without any substantial spillage.

It is another object of the invention to provide an improved pneumatic conveying system which is simple in construction, low in cost and which allows rapid loading of open containers such as gondola cars.

It is another object of the invention to provide an improved pneumatic conveying system wherein the ve-,-

locity of the conveying gas and the velocity of the ma terial being conveyed is reduced while both are moving in a substantially horizontal direction and at such a position that the final movement of the particles is brought about substantially solely by gravity.

Further objects and advantages of the invention will become apparent upon reference to the following speci lication and claims and appended drawings wherein:

Figure l is a plan view of a pneumatic conveying system for wood chips according to the present invention;

Figure 2 is a vertical elevation of the conveying system of Figure 1 showing the loading of a gondola car; and

Figure 3 is a further vertical elevation of the conveying system of Figures 1 and 2.

Referring to the figures of the drawing wherein there is shown a conveyor system adapted to handle wood chips, a fan 10 is connected to a main conduit 12 which receives wood chips from a chipper hog M which may be of the type described in my copending application Serial No. 362,790. The conduit 12 extends to a point.

adjacent the delivery position where it is connected to a percentage valve 16 which feeds into reduced diameter secondary conduits 18 and 2%. The percentage valve may be of any conventional type such as the type having a blade extending up into the valve so as to divert the chips to either line or to split the valve to allow the chips to enter both conduits l8 and 20 at the same time. Each secondary conduit 18 and 20 is connected to an expansion section 22 and 24 which couples the conduit to a larger diameter elbow 26 and 28. The elbows 26 and 28 are swivelly mounted on the end of the expansion sections 22 and 24 and are provided with down pipes 30 and 32 having flared upper ends 34 and 36 hinged to the elbows at 38. The down pipes 30 and 32 extend downwardly over a suitable receptacle such as a gondola car 40 on tracks 42. Because of the swivel mounting of the elbows 26 and 2% on the expansion section 22 and In the particular installation depicted the main con duit 12 which is the conveying conduit and which handles the chips over practically the entire distance to be covered by the conveying system, is of a diameter of 15 inches. After the percentage valve, the secondary conduits 18 and 24) are of a diameter of 11 inches to give. a total cross sectional conveying space approximately equal to that available in the main conduit 12. The.

elbows 26 and 28 are of a diameter of 21 inches which reduces the velocity of air fiow to approximately one.

fourth that of the conveying velocity obtained in conduit 12. The air at this point thus loses its ability to convey. the chips which are then carried on by momentum past the elbow into the down pipes where they fall by gravity into the gondola 40 or other container.

It is important that the expansion in the size of sec ondary pipes 18 and 20 occurs at a position in advance Patented Jan. I958,

ofthe down pipes where the momentum of the chips will then carry the chips to a position where they may fall vertically under the influence of gravity, since the air is no longer possessed of a velocity sufficient to act as a conveyor. If the expanded section is inserted ahead of this point the chips will tend to pile up and clog the conduits, while if the expanded section is inserted behind this position the chips will be blasted into the container or gondola car under the influence of the air so as to make it extremely diflicult if not impossible to load the car. In the particular system illustrated the distance A from thesmall end of the expansion section 22 to the centerline of the down pipe 30 is nine andone halffeet, While the distance B from thelarge end of the expansion section to the centerline of, the down pipe is four and a'half feet or approximately two and one half times the diameter of'the large end of the expansion section. 7

By utilizing two reduced diameter secondary conduits 18 and 20 having a total cross sectional diameter approximately equal to that of the main conduit 12' the diameter of the expanded elbows 26'and 28'is reduced to a convenient, size, which would not be the case if'the expanded;

sections were simply attached to the end of' the main conduit 12'. In addition to this the use of the particular arrangement shown in the drawings permits almost continuous loading of gondola cars or trucks as will be apparent from reference to Figure 3 of the drawings. Referring to that figure and assuming that the percentage valve is so set as to cause both down pipes 39 and- 32 to deliver chips tothe car, the center and left end of'the car may be completely loaded whereupon the flow of chips through pipe 30 may be cut off and the car moved to the left while down pipe 32 continues to deliver chips. The car may be moved until its right end is under down pipe 30 while the end of down pipe 32 isimmediately abovethe left end of a following car. Down pipe 30 may then be used'to finish loading car 40 while down pipe 32 is simultaneously loading the left end of the following car, not shown. After car 40 is loaded the train of cars may be again moved to the left to place the fo-lloving car squarely under the down pipes as car $0 is placed in Figure 3. It will thus be seen that the loading process may be carried on substantially continuously and because the chips are falling by gravity rather than under the influence of ajconveying fluid there is no difficulty with the top layer of chips being blown out of the cars. In a similar manner it is possible to load trucks and trucks may be loaded simultaneously with railroad cars if the trucks are backed up to the cars from the left as shown in Figure 2.

It will be apparent from the foregoing that there has been provided a novel pneumatic conveying system which permits the loading of open containers in a simple, rapid and substantially continuous manner. The equipment is simple, relatively low in cost and requires a minimum of. maintenance.

The invention may be embodied inother specific forms without departing from the spirit or essential characteristics thereof. The present embodiment is therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning andrange of'equivalency of the claims are therefore intended tobe embraced therein.

What is. claimed and desired to be secured by United States Letters Patent is:

1. A pneumatic conveying system comprising, a blower, a main conduit connected to said blower, means for feeding material to be conveyed into said main conduit', said blower supplying gas to said main conduit at a velocity sufiicient to, convey said material, an, elbow, a downwardly extending pipe connected to saidelbow, and" a conduit of expanding diameter having its smaller end connected to said main conduit and its larger end connected tosaid-elbow in a manner-topermit relative movement between said downwardly directed pipe and said expanding conduit, the diameter of said larger end of said expanding diameter conduit being such as to reduce the velocity of said gas below the velocity necessary to convey the material horizontally, said reduction in velocity occurring at such a position that the material being conveyed reaches a point above the downwardly extending pipe by means of its momentum and is thereafter conveyed downwardly in said downwardly extending pipe at a rate in excess of that caused by gravity.

2. A pneumatic conveying system comprising, a blower, a main conduit connected to said blower, means for feeding material to be conveyed into said main conduit, said blower supplying gas to said main conduit at a velocity, suifieient to convey said material, anelbow, a downwardly extending pipe hingedly connected to said elbow, and a conduit of expanding diameterv having its smaller end connected to said main conduit and its larger end connected to said elbow, the connections of: said expanding diameter conduitbeing such that said elbow is free to swivel with respect to said main conduit, the diameter of said larger end of said expanding diameter conduit being such as to reduce the velocity of said gas below the velocity necessary to convey the material horizontally, said'reduction in velocityoccurring atsuch-a position that the material being conveyed-reaches a point for feeding material to be conveyed into said main.-

conduit, said blower supplying-gas to said main conduit at a velocity suific-ient to-convey said material, a percentage valve connected" to said main conduit, secondaryconduits of a smaller diameter than said mainconduin connected to said percentage valve, an elbow associated. with each secondary conduit, a downwardly extending pipe connectedto each elbow, and a conduit-of expanding diameter associated with each secondary conduit and having its smaller end-connected to a secondary-conduit and its larger endconnected totheelbow, the diameter of the larger ends of said expandingdiameter conduits being such asto reducethe velocity of'said'gas belowthe. velocity necessary to convey the material horizontally,

said reduction in velocity occurring at such a position for feeding materialto be conveyed into said main con-.

duit, said blower supplying gas to saidmain conduit; at a velocity sufficient to convey said-material, a percentage valve connected to said main conduit, secondary conduits of a smaller diameter than said main conduit connected to said 'percentage valve, an elbow swivelly associated.

with each secondary conduit, a downwardly extending pipe hingedly connected to eachelbow, and a conduit of expanding diameter associated with each secondary conduit and having its smaller end connected to the secondary conduit and its larger end connected to. the. elbow, the diameter of the'larger ends of saidexpandingdiameter conduits being such as to reduce the velocity.

of said gas below the velocity necessary to convey the.

material horizontally, said reductioninivelocity occurring at such a position that: the material being conveyed reaches a point above the downwardly extendingpipes.

by means of its momentum and is thereafter conveyed: downwardly in saiddownwardly extending pipe at a rate in excess'of that caused by gravity.

5. A pneumatic conveying system as set out in claim 4 wherein the diameter of the large end of said expanding diameter conduit is such as to reduce the velocity of said gas to approximately one fourth its velocity in said secondary conduits.

6. A pneumatic conveying system as set out in claim 4 wherein the sum of the cross sectional areas of said secondary conduits is substantially equal to the cross sectional area of said main conduit.

7. A pneumatic conveying system as set out in claim 4 wherein the distance from the large end of said expanding diameter conduits to a projection of the centerlines of said downwardly extending pipes is approximately two and a half times the diameter of said large end.

References Cited in the file of this patent UNITED STATES PATENTS 285,047 Lewis Sept. 18, 1883 475,635 Taylor -1 May 24, 1892 672,409 Scheidegger Apr. 16, 1901 891,191 Schinn June 16, 1908 1,605,196 Ligon Nov. 2, 1926 1,818,367 Wallace Aug. 11, 1931 2,733,993 Thober Feb. 7, 1956 

